One of my speakers sounds like it's underwater.

[TLS Guy]

I may just throw a pair of these in there and see what happens

Waste of money. You can't swap drivers. The sensitivity is close, but that Dayton driver is breaking up before the crossover point and the porting and crossover will not be correct. If you want to use those speakers you need to recone them yourself, or pay to have them refoamed.

 

[isolar8001]

I may just throw a pair of these in there and see what happens

Bad Idea as TLSGuy has stated.

Rather than all of us shooting in the dark here...
Is/are the foam/surrounds good ?
Do they need new surrounds ? Thats easy and cheap if that's all it is.

If they are popping and breaking up with good surrounds, you need new woofers....the voice coils are blown.
Pictures of the woofers ?

 

[Gil_Pena]

Remember, keep them away from your aquarium ....

Hahahaha

 

[Gil_Pena]

Hmmm says my files are too large . Pics of course. The surrounds look very new. Almost perfect.foam.

 

[Gil_Pena]

So what does a speaker that needs refoamed sound like? I found this. My speaker definitely makes a crazy popping sound . Very loud. I ordered a multimeter reader. My circuitry skills are minimal but not zero. She be coming tomorrow and I will report back the results

 

[isolar8001]

So what does a speaker that needs refoamed sound like? I found this. My speaker definitely makes a crazy popping sound . Very loud. I ordered a multimeter reader. My circuitry skills are minimal but not zero. She be coming tomorrow and I will report back the results

Refoamed means replacing the surround that holds the cone to the frame...you said your surrounds look and feel fine.
From the loud popping noise you describe (and that's the best way to describe it), you need to recone...in simple terms, that woofer is blown.
Another test is to push the woofer cone in and let it come out (repeatedly and gently). If you feel any rubbing, the woofer is blown. I have seen woofers that are blown without the rubbing though.

A Multimeter won't tell you anything, it will still measure some resistance even if it's bad. You could measure the crossover components to see if you might need to replace the capacitors. (old speakers can be fun !)

Speaker Exchange offers a recone service if you feel you cant do it yourself.

JBL 118H Aftermarket Recone Kit - Speaker Exchange

Brand New JBL 118H Aftermarket Recone Kit 8 ohms. Note that the original speaker had a white cone with butyl rubber surround. This kit has black cone with foam surround. These are the only parts available for this model. Parts Specifications: Cone: 10″ black cone with foam surround, 2.125″ deep...

reconingspeakers.com

 

[Gil_Pena]

Racone and refoam are different? Sorry still learning. Vintage seems pretty fun so far

 

[TLS Guy]

Racone and refoam are different? Sorry still learning. Vintage seems pretty fun so far

I don't know how a speaker issue causes popping. Are you sure you really swapped the audio channels to the speakers? I have a strong feeling you did not.

So, to make sure you did, I want you to leave everything as it is, but physically move the speakers, so that what was the left speaker is now the right speaker, and what was the right speaker is now the left. Do NOT move the speaker wiring only the speakers. Now tell us what happens.